US4118611A - Buckling spring torsional snap actuator - Google Patents

Buckling spring torsional snap actuator Download PDF

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Publication number
US4118611A
US4118611A US05/829,039 US82903977A US4118611A US 4118611 A US4118611 A US 4118611A US 82903977 A US82903977 A US 82903977A US 4118611 A US4118611 A US 4118611A
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US
United States
Prior art keywords
spring
buckling
key top
rocker
mounting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/829,039
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English (en)
Inventor
Richard Hunter Harris
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IBM Information Products Corp
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International Business Machines Corp
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Filing date
Publication date
Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Priority to US05/829,039 priority Critical patent/US4118611A/en
Priority to CA303,019A priority patent/CA1098947A/en
Priority to JP8410478A priority patent/JPS5437281A/ja
Priority to EP78430007A priority patent/EP0001031B1/fr
Priority to DE7878430007T priority patent/DE2860193D1/de
Priority to IT26396/78A priority patent/IT1109970B/it
Application granted granted Critical
Publication of US4118611A publication Critical patent/US4118611A/en
Assigned to MORGAN BANK reassignment MORGAN BANK SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: IBM INFORMATION PRODUCTS CORPORATION
Assigned to IBM INFORMATION PRODUCTS CORPORATION, 55 RAILROAD AVENUE, GREENWICH, CT 06830 A CORP OF DE reassignment IBM INFORMATION PRODUCTS CORPORATION, 55 RAILROAD AVENUE, GREENWICH, CT 06830 A CORP OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: INTERNATIONAL BUSINESS MACHINES CORPORATION
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/02—Details
    • H01H13/26—Snap-action arrangements depending upon deformation of elastic members
    • H01H13/28—Snap-action arrangements depending upon deformation of elastic members using compression or extension of coil springs
    • H01H13/30—Snap-action arrangements depending upon deformation of elastic members using compression or extension of coil springs one end of spring transmitting movement to the contact member when the other end is moved by the operating part
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2235/00—Springs
    • H01H2235/012—Euler spring

Definitions

  • the invention relates to snap action switches and switch actuators in general and in particular to rocker type switch or toggle switches having snap action of a pivotal member.
  • U.S. Pat. No. 2,810,031 illustrates a snap action rocker type of switch in which a coil spring is used to drive a pivoted rocker actuator back and forth.
  • an additional member must be added between the push button and the rocker element to assure the appropriate direction of travel upon initiation of action and to provide a restoring action upon release.
  • An additional member is used to create the proper torsional moment direction to rock the rocker in the desired manner. This additional element may be a source of instability and an eventual source of failure should sticking or wear interfere with the desired operation.
  • a snap action rocker switch is shown in U.S. Pat. No. 3,491,218, but an additional actuating member is positioned between the key button and the rocker in order to insure the proper direction of rotation in the rocker element.
  • an object of the present invention to provide an improved snap action rocker switch utilizing a buckling compression column and specifically the reaction moment of the buckling column to rock the rocker element over center and to restore it to its initial position on release of the buckled column spring.
  • FIG. 1A illustrates a preferred embodiment of the invention in a cross-sectional view taken parallel to the longitudinal axis of the compression spring.
  • FIG. 1B illustrates the mechanism in FIG. 1A with the key top partially depressed.
  • FIG. 1C illustrates the mechanism in FIGS. 1A and 1B with the key top further depressed to the point at which catastrophic buckling in the spring member occurs.
  • FIG. 1D illustrates the mechanism as shown in FIGS. 1A through 1C with the key top further depressed after catastrophic buckling of the spring member has occurred.
  • FIG. 2 illustrates the key force and displacement characteristic of the present rocking switch actuator constructed as illustrated in FIGS. 1A through 1D.
  • FIG. 1A of the drawings where a vertical section taken through a representative key actuator according to the present invention is shown.
  • the key top or key button 1 is shown in its undeflected position before the application of a force to the top of the key button illustrated by the arrow labeled F in FIG. 1B.
  • the catastrophically buckling compression column spring element 2 is shown as a helical compression spring member.
  • My own prior U.S. Pat. No. 3,699,296 will be incorporated here by reference in its entirety to serve as a teaching of the characteristics that compression column springs of the catastrophic buckling type require. It will be understood by those of skill in the art that other configurations for the compression column springs such as thin wires, rods or flat leaves may be used.
  • a housing 3 is provided as shown to contain the stem or barrel 6 of the key top 1.
  • the key member 1 and the housing 3 are preferably formed of plastic, injection molded to the shape desired, or of some other similar inexpensive non-conductive material.
  • injection molded plastic parts are utilized for the key top 1, the housing 3 and for the rocking actuator or coupling member 4.
  • the coupling member 4 is provided with a mounting point 7 over which the helical compression column spring 2 fits.
  • the rocking coupling member 4 is formed of injection molded conductive plastic for example, in the preferred embodiment, and has a general V or rocker shape with a pivot point located generally in line with the edge of the compression column spring 2 as illustrated by point 8 in FIG. 1A.
  • Individual electrical contacts 5A, 5B, and 5C are shown mounted on a circuit board or other similar non-conductive substrate 9. The connections to the contacts 5A through 5C which would be made to utilize the electrical characterstics achieved by rocking member 4 back and forth between contacts 5A, 5B, and 5C are not shown, since these would be obvious to those of skill in the art.
  • the contacts 5A through 5C in the preferred embodiment constitute plates in a capacitive switching system and it will be understood that the contacts will be covered by a thin layer of dielectric material to create a capacitive action when actuator 4 is in close proximity to any two of the plates 5A through 5C.
  • a capacitive coupling exists between plates 5A and 5B through the medium of actuator 4.
  • Plates 5A and 5C with rocker 4 positioned as illustrated in FIG. 1A are not as capacitively coupled together as contacts 5A and 5B.
  • contacts 5A and 5C would be called the normally open contact set. This condition could be indicative of either an "ON” or an "OFF" condition and the electrical logic of the using system, not shown, could be configured to make advantage of either the normally open or normally closed condition as indicative of actuation.
  • FIG. 1B illustrates the mechanism as shown in FIG. 1A but with a force F applied to the key top 1 to depress it from its uppermost position shown in FIG. 1A.
  • the upward extent of travel is limited by the projection 10 interfering with ledge 11 in the housing 3.
  • Projection 10 is made a portion of the barrel 6 (or stem) of key top 1.
  • the downward limit of travel is created by interference between the under surface of key top 1 identified by numeral 13 and the upper surface of the housing 3 identified by numeral 12.
  • FIG. 1C illustrates the mechanism as shown in FIGS. 1A and 1B but with key top 1 depressed still further to a point at which catastrophic buckling of spring member 2 has just occurred.
  • the end of the compression column spring 2 which was mounted in mount 14 in barrel 6 has pivoted free about one edge of the coil spring itself and, as will be understood by those of skill in the art and as taught in my own prior U.S. Pat. No. 3,699,286, this action occurs in a rapid and catastrophic manner to produce a sudden snap action.
  • the rotational moment applied to the rocker member 4 rocks it over center to the right as shown in FIG. 1C so that capacitive coupling exists between contacts 5A and 5C through the medium of the right leg of actuator 4.
  • Capacitive contacts 5A and 5B are no longer coupled as shown.
  • the sudden snap action provides a tactile feedback to a human operator due to the sudden decrease in force as will be described more specifically later, and also produces an audible feedback since the sudden pivoting of the rocker member 4 produces a clicking noise.
  • FIG. 1D illustrates the mechanism as shown in FIGS. 1A through 1C, but with key top 1 further depressed toward its utmost depression which would create contact between surfaces 13 and 12 as noted previously. No further rotation or motion occurs in this condition up to the limiting point of travel in the downward direction for key top 1. Upon release of pressure, the compression column spring 2 will relax and return in the direction from which it came.
  • FIG. 2 a typical key force and displacement profile for the mechanism of the invention as illustrated in FIGS. 1A through 1D is shown.
  • the key force is that force F required to depress the key top 1 and is shown on the vertical axis in the force and travel diagram.
  • a typical key travel in inches is shown and is meant to represent the amount of vertical deflection that key top 1 experiences due to increase in force F.
  • FIG. 2 the position approximated by the mechanism shown in FIG. 1A is identified on the key force profile by a small 1A designation.
  • the other figures 1B through 1D which have their various relative positions on the key force and deflection diagram indicated as shown. It will be observed that a fair amount of physical hysteresis, which is of importance in creating non-teasibility, exists in the structure since the mechanism does not snap back over center until a point below that at which snap over occurred is reached.
  • depression of the key button 1 moves the key button and its stem 6 into the housing 3, creating longitudinal compression and lateral deflection of the helical compression spring 2.
  • An initial counter-clockwise moment is exerted on the rocker member 4 which is approximately equal to the force F times the distance between the pivot point 8 of the rocking member 4 and the center line of the spring.
  • the upper end of the helical spring 2 is held squarely against the key button 1 by a clockwise moment created by a force equal to approximately F times the diameter of the spring divided by two.
  • the rocker member 4 will initially be held firmly over the contacts 5A and 5B.
  • both the top and bottom reaction moments in spring 2 are decreased because F is transmitted through the center section of spring 2.
  • the rocker member rocks to a position squarely over contacts 5A and 5C and the top of spring 2 rocks about the right hand edge of its topmost coil.
  • the constraints upon the depression column spring have changed from an initial end clamped condition to an end clamped-pinned condition. This sudden change provides the tactile response of the key and is accompanied by a sudden rocking action of the rocker member 4 which creates an acoustic feedback as well.
  • rocker member 4 Upon release of pressure, rocker member 4 will be rapidly snapped in the counter clockwise direction at a position in the key travel that is less than that required initially to cause a clockwise snapping action discussed previously.
  • This effect is due to the catastrophic buckling point, in this case the unbuckling or restoration point, is reached at a key travel position measured from the undepressed condition that is less than that which created buckling in the first place.
  • the reason for this is that the end clamped-pinned condition that exists after buckling has occurred in the downward stroke of the key button, the end conditions change as noted above and the degree of key travel required will be less than that for the initial end clamped condition at which the catastrophic buckling spring member initially resides.
  • a second cause for the difference between the unbuckling point in the key travel and the buckling point is that the snapping of the rocker member 4 creates an instantaneous increase in the lateral deflection of the center of the helical compression spring 2. This requires that the key travel must be less in order to cause the same lateral deflection that initially caused the clockwise snap.
  • a differential capacitance circuit is used in the preferred embodiment illustrated to detect actuation of the key switch.
  • Either a normally open or normally closed capacitive scheme would work as well and it should be clearly understood that normal electrical contacts for normally open normally closed conduction between contacts 5A, 5B, and 5C could be used equally well.
  • a variety of other electrical signal producing means might be employed, such as inductive, piezo electric or light interruption sensors could be employed instead of the electrical contacts 5A, 5B, and 5C.
  • the overall structure would remain the same as will be appreciated by those of skill in the art.

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  • Push-Button Switches (AREA)
  • Input From Keyboards Or The Like (AREA)
US05/829,039 1977-08-30 1977-08-30 Buckling spring torsional snap actuator Expired - Lifetime US4118611A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US05/829,039 US4118611A (en) 1977-08-30 1977-08-30 Buckling spring torsional snap actuator
CA303,019A CA1098947A (en) 1977-08-30 1978-05-10 Buckling spring torsional snap actuator
JP8410478A JPS5437281A (en) 1977-08-30 1978-07-12 Accelerating device with key
DE7878430007T DE2860193D1 (en) 1977-08-30 1978-07-20 Push button switch with snap action
EP78430007A EP0001031B1 (fr) 1977-08-30 1978-07-20 Commutateur électrique à touche, à action brusque
IT26396/78A IT1109970B (it) 1977-08-30 1978-08-02 Azionatore commutatore a scatto

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US05/829,039 US4118611A (en) 1977-08-30 1977-08-30 Buckling spring torsional snap actuator

Publications (1)

Publication Number Publication Date
US4118611A true US4118611A (en) 1978-10-03

Family

ID=25253373

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/829,039 Expired - Lifetime US4118611A (en) 1977-08-30 1977-08-30 Buckling spring torsional snap actuator

Country Status (6)

Country Link
US (1) US4118611A (it)
EP (1) EP0001031B1 (it)
JP (1) JPS5437281A (it)
CA (1) CA1098947A (it)
DE (1) DE2860193D1 (it)
IT (1) IT1109970B (it)

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4274752A (en) * 1979-04-02 1981-06-23 International Business Machines Corporation Keyboard multiple switch assembly
JPS6081719A (ja) * 1983-10-03 1985-05-09 インタ−ナショナル　ビジネス　マシ−ンズ　コ−ポレ−ション 接点開閉装置
US4543562A (en) * 1982-08-23 1985-09-24 Rca Corporation Mechanically-actuated touchbars and touchplates using multiple-closure switches
US4543563A (en) * 1982-08-23 1985-09-24 Rca Corporation Mechanically-actuated transparent touchbars and touchplates
EP0163149A2 (en) * 1984-05-29 1985-12-04 International Business Machines Corporation Membrane keyboard switch mounting
EP0209628A2 (en) * 1985-07-09 1987-01-28 Carlingswitch, Inc. Push button switches
US4859820A (en) * 1988-03-31 1989-08-22 American Telephone And Telegraph Company Quiet key switch
US4931606A (en) * 1989-04-28 1990-06-05 International Business Machines Corporation Key switch mechanism and membrane actuator
US5012055A (en) * 1988-12-12 1991-04-30 Alps Electric Co., Ltd. Spring loaded push-button switch having predictable switching time despite varying spring characteristics
US5268545A (en) * 1992-12-18 1993-12-07 Lexmark International, Inc. Low profile tactile keyswitch
US5349281A (en) * 1991-03-22 1994-09-20 Hm Electronics, Inc. Battery charging system and method of using same
US5380972A (en) * 1993-11-19 1995-01-10 Motorola, Inc. Rocker switch
US6570106B1 (en) 2000-07-10 2003-05-27 Steven L. Merrick Movable electric switches that move to reveal underlying control areas
US20050214065A1 (en) * 2001-11-30 2005-09-29 Renault S.A.S. Device for fixing a plastic part on a body shell structure
US20140209601A1 (en) * 2013-01-30 2014-07-31 Agm Container Controls, Inc. Breather Valve Assemblies
US9660229B2 (en) 2011-08-01 2017-05-23 Ingersoll-Rand Company Battery pack release with tactile feedback for cordless power tools
US9850974B1 (en) 2013-03-14 2017-12-26 Hrl Laboratories, Llc Buckling column load switch spring
US9884416B2 (en) 2011-08-01 2018-02-06 Ingersoll-Rand Company Devices including power tools with non-binding linear slides and associated methods
US20190033971A1 (en) * 2017-07-28 2019-01-31 Synaptics Incorporated Haptic tactile feedback with buckling mechanism
US10840038B2 (en) 2015-12-02 2020-11-17 Juwilia LIM Keyswitch mechanism with horizontal motion return mechanism
US10987274B2 (en) 2016-08-02 2021-04-27 Adel Bougatef Method and apparatus for providing percussive ventilation therapy to a patient airway
US11092172B2 (en) 2019-07-12 2021-08-17 Dennis Keith Reust Seismic vibrator servo valve with proportional linear pressure feedback
US11346966B2 (en) 2020-06-23 2022-05-31 Dennis Keith Reust System and method to transfer inertial mass

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2282703A (en) * 1993-10-05 1995-04-12 Daw Shen Chen Mechanical key switch

Citations (7)

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Publication number Priority date Publication date Assignee Title
US2810031A (en) * 1954-11-26 1957-10-15 Hellstrom Gosta Ludvig Electric switch
US3491218A (en) * 1968-01-05 1970-01-20 Cutler Hammer Inc Pushbutton switch with pivotally mounted actuator
US3699296A (en) * 1971-05-21 1972-10-17 Ibm Catastrophically buckling compression column switch and actuator
US3731030A (en) * 1970-06-17 1973-05-01 Holzer Patent Ag Pushbutton switch assembly with pivotable conductive bridging member and multiple conductive path printed circuit board
US3842229A (en) * 1973-07-05 1974-10-15 Texas Instruments Inc Keyboard pushbutton switch
US3863040A (en) * 1974-02-14 1975-01-28 Oak Industries Inc Switch mechanism
US3899648A (en) * 1973-03-16 1975-08-12 Alps Electric Co Ltd Nodally operated push-button switch

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Publication number Priority date Publication date Assignee Title
US3165611A (en) * 1961-07-18 1965-01-12 Carling Electric Inc Spring biased-spring actuated momentary switch
US3200657A (en) * 1962-09-27 1965-08-17 Cts Corp Electric switch
US3619528A (en) * 1970-08-14 1971-11-09 Carling Electric Inc Momentary plunger switch
US3979571A (en) * 1974-02-14 1976-09-07 Oak Industries Inc. Buckled spring switch mechanism with latching pushbutton
DE7504400U (de) * 1975-02-13 1975-06-05 Marquardt J & J Elektrischer Schalter

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2810031A (en) * 1954-11-26 1957-10-15 Hellstrom Gosta Ludvig Electric switch
US3491218A (en) * 1968-01-05 1970-01-20 Cutler Hammer Inc Pushbutton switch with pivotally mounted actuator
US3731030A (en) * 1970-06-17 1973-05-01 Holzer Patent Ag Pushbutton switch assembly with pivotable conductive bridging member and multiple conductive path printed circuit board
US3699296A (en) * 1971-05-21 1972-10-17 Ibm Catastrophically buckling compression column switch and actuator
US3899648A (en) * 1973-03-16 1975-08-12 Alps Electric Co Ltd Nodally operated push-button switch
US3842229A (en) * 1973-07-05 1974-10-15 Texas Instruments Inc Keyboard pushbutton switch
US3863040A (en) * 1974-02-14 1975-01-28 Oak Industries Inc Switch mechanism

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4274752A (en) * 1979-04-02 1981-06-23 International Business Machines Corporation Keyboard multiple switch assembly
US4543562A (en) * 1982-08-23 1985-09-24 Rca Corporation Mechanically-actuated touchbars and touchplates using multiple-closure switches
US4543563A (en) * 1982-08-23 1985-09-24 Rca Corporation Mechanically-actuated transparent touchbars and touchplates
JPH0561733B2 (it) * 1983-10-03 1993-09-07 Lexmark Int Inc
JPS6081719A (ja) * 1983-10-03 1985-05-09 インタ−ナショナル　ビジネス　マシ−ンズ　コ−ポレ−ション 接点開閉装置
US4528431A (en) * 1983-10-03 1985-07-09 International Business Machines Corporation Rocking switch actuator for a low force membrane contact switch
EP0163149A2 (en) * 1984-05-29 1985-12-04 International Business Machines Corporation Membrane keyboard switch mounting
EP0163149A3 (en) * 1984-05-29 1986-03-12 International Business Machines Corporation Membrane keyboard switch mounting
US4605828A (en) * 1984-05-29 1986-08-12 International Business Machines Corporation Membrane keyboard switch mounting
EP0209628A2 (en) * 1985-07-09 1987-01-28 Carlingswitch, Inc. Push button switches
EP0209628A3 (en) * 1985-07-09 1988-01-07 Carlingswitch, Inc. Push button switches
US4640998A (en) * 1985-07-09 1987-02-03 Carlingswitch, Inc. Push button switch with compound contact lever action
US4859820A (en) * 1988-03-31 1989-08-22 American Telephone And Telegraph Company Quiet key switch
US5012055A (en) * 1988-12-12 1991-04-30 Alps Electric Co., Ltd. Spring loaded push-button switch having predictable switching time despite varying spring characteristics
US4931606A (en) * 1989-04-28 1990-06-05 International Business Machines Corporation Key switch mechanism and membrane actuator
EP0395561A2 (en) * 1989-04-28 1990-10-31 Lexmark International, Inc. Key switch mechanism with membrane actuator
EP0395561A3 (en) * 1989-04-28 1991-03-06 Lexmark International, Inc. Key switch mechanism with membrane actuator
US5349281A (en) * 1991-03-22 1994-09-20 Hm Electronics, Inc. Battery charging system and method of using same
US5268545A (en) * 1992-12-18 1993-12-07 Lexmark International, Inc. Low profile tactile keyswitch
US5380972A (en) * 1993-11-19 1995-01-10 Motorola, Inc. Rocker switch
US6570106B1 (en) 2000-07-10 2003-05-27 Steven L. Merrick Movable electric switches that move to reveal underlying control areas
US7731444B2 (en) * 2001-11-30 2010-06-08 Renault S.A.S. Device for coupling a plastic part and a body shell structure
US20050214065A1 (en) * 2001-11-30 2005-09-29 Renault S.A.S. Device for fixing a plastic part on a body shell structure
US9660229B2 (en) 2011-08-01 2017-05-23 Ingersoll-Rand Company Battery pack release with tactile feedback for cordless power tools
US9884416B2 (en) 2011-08-01 2018-02-06 Ingersoll-Rand Company Devices including power tools with non-binding linear slides and associated methods
US20140209601A1 (en) * 2013-01-30 2014-07-31 Agm Container Controls, Inc. Breather Valve Assemblies
US9850974B1 (en) 2013-03-14 2017-12-26 Hrl Laboratories, Llc Buckling column load switch spring
US10840038B2 (en) 2015-12-02 2020-11-17 Juwilia LIM Keyswitch mechanism with horizontal motion return mechanism
US10987274B2 (en) 2016-08-02 2021-04-27 Adel Bougatef Method and apparatus for providing percussive ventilation therapy to a patient airway
US20190033971A1 (en) * 2017-07-28 2019-01-31 Synaptics Incorporated Haptic tactile feedback with buckling mechanism
US10698486B2 (en) 2017-07-28 2020-06-30 Synaptics Incorporated Haptic tactile feedback with buckling mechanism
US11054908B2 (en) 2017-07-28 2021-07-06 Synaptics Incorporated Haptic tactile feedback with buckling mechanism
US11092172B2 (en) 2019-07-12 2021-08-17 Dennis Keith Reust Seismic vibrator servo valve with proportional linear pressure feedback
US11346966B2 (en) 2020-06-23 2022-05-31 Dennis Keith Reust System and method to transfer inertial mass

Also Published As

Publication number Publication date
DE2860193D1 (en) 1981-01-08
IT1109970B (it) 1985-12-23
JPS5437281A (en) 1979-03-19
EP0001031B1 (fr) 1980-10-01
JPS5741774B2 (it) 1982-09-04
CA1098947A (en) 1981-04-07
EP0001031A1 (fr) 1979-03-07
IT7826396A0 (it) 1978-08-02

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Owner name: MORGAN BANK

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Effective date: 19910327

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